This invention relates to a circular knitting machine incorporating a device for setting to work knitting cams, in particular for hose knitting.
Many particular knitting types are to be carried out on knitting machines and in particular hose knitting machines which are generally based on changing the number of the needles brought to knit and variation of the paths of the butts of such needles internally of the needle cylinder cam assemblies.
Knitting cams are provided for such variations which can be pushed in or inserted and withdrawn as required, of the needle cylinder cam assemblies so as to alter the path of the needle butts which are moved internally of the cam assemblies. These knitting cams can be pushed into two positions and the needles are provided some with long butts and some with short butts, such that by changing the pushed-in position, the number of the needles brought to knit is also changed.
Known are devices for pushing in the knitting cams which comprise generally a lever system driven by cams carried on the main drum, having the function of the machine control, and driving the various knitting cams which must be pushed in and withdrawn from the cam assemblies.
In practice the main drum carries on its outer surface a given number of elevations or drive cams which, through a lever system, drive the knitting cams in accordance with a knitting scheme set by these drive cams.
These devices have the disadvantage of being mechanically complicated owing to the need of providing several lay levers and drive cams on the main drum.
In particular the construction of the main drum is to be altered to adapt it for the knittings envisaged by the hose manufacturer, as well as a complex variety of drive cams to be assembled each time to the main drum.
Another drawback resulting from the high number of mechanical parts is that special attention is to be devoted to adjusting all the members during the machine tune-up.
In time, moreover, all these mechanical parts are subjected to wear and this cumbersome adjusting operation must be repeated periodically to take up any play.